[2] It is a pitch describing one's interest in the position, skills and relevant experience for the advertised job.
Employers may look for individualized and thoughtfully written cover letters as one method of screening out applicants who are not sufficiently interested in their positions and/or lack the necessary basic skills.
Résumé cover letters may also serve as marketing devices for prospective job seekers.
While the resume outlines the professional journey, a cover letter allows the applicant convey their personality, passion, and potential contributions to the prospective employer.
Cover letters may serve the purpose of trying to catch the reader's interest or persuade the reader of something, or they may simply be an inventory or summary of the documents included along with a discussion of the expected future actions the sender or recipient will take in connection with the documents.